Determining transformations of media signals with embedded code signals

• US 6,424,725 B1
• Filed: 05/08/2000
• Issued: 07/23/2002
• Est. Priority Date: 05/16/1996
• Status: Expired due to Fees

• Current Assignee: Digimarc Corporation
• Original Assignee: Digimarc Corporation
• Inventors: Sharma, Ravi K., Rhoads, Geoffrey B.
• Primary Examiner(s): Couso, Jose L.
• Application Number:
  US09/566,533
• Time in Patent Office: 806 Days
• Field of Search: 382/100, 382/232, 382/284, 395/135, 358/454, 358/448, 358/450, 358/142, 358/124, 380/4, 380/23, 380/24, 283/6, 283/93, 283/94, 348/475, 235/494
• US Class Current: 382/100
• CPC Class Codes: G06T 1/0064 Geometric transfor invariant watermarking, e.g. affine transform invariant
• CPC Class Codes: G06T 2201/0051 Embedding of the watermark in the spatial domain
• CPC Class Codes: G06T 2201/0052 Embedding of the watermark in the frequency domain
• CPC Class Codes: G06V 30/40 Document-oriented image-based pattern recognition
• CPC Class Codes: G10L 19/018 Audio watermarking, i.e. embedding inaudible data in the audio signal
• CPC Class Codes: H04N 1/00005 relating to image data
• CPC Class Codes: H04N 1/00037 Detecting, i.e. determining the occurrence of a predetermined state H04N1/00031 takes precedence
• CPC Class Codes: H04N 1/00079 remotely
• CPC Class Codes: H04N 1/32122 in a separate device, e.g. in a memory or on a display separate from image data
• CPC Class Codes: H04N 1/32144 embedded in the image data, i.e. enclosed or integrated in the image, e.g. watermark, super-imposed logo or stamp
• CPC Class Codes: H04N 1/32149 Methods relating to embedding, encoding, decoding, detection or retrieval operations
• CPC Class Codes: H04N 1/32154 Transform domain methods H04N1/32309 takes precedence
• CPC Class Codes: H04N 1/3216 using Fourier transforms
• CPC Class Codes: H04N 1/3232 Robust embedding or watermarking
• CPC Class Codes: H04N 1/32352 Controlling detectability or arrangements to facilitate detection or retrieval of the embedded information, e.g. using markers for decoding, detection or retrieval operations H04N1/32149 and subgroups take precedence
• CPC Class Codes: H04N 21/23892 involving embedding information at multiplex stream level, e.g. embedding a watermark at packet level
• CPC Class Codes: H04N 21/8358 involving watermark protecting executable software by watermarking G06F21/16; image watermarking in general G06T1/0021; watermarks inserted in still images for transmission purposes H04N1/32144; inserting watermarks during video coding H04N19/467
• CPC Class Codes: H04N 2201/3205 of identification information, e.g. name or ID code H04N2201/3209 takes precedence
• CPC Class Codes: H04N 2201/3207 of an address
• CPC Class Codes: H04N 2201/3225 of data relating to an image, a page or a document
• CPC Class Codes: H04N 2201/3226 : of identification information or the like, e.g. ID code, index, title, part of an image, reduced-size image
• CPC Class Codes: H04N 2201/3233 : of authentication information, e.g. digital signature, watermark
• CPC Class Codes: H04N 2201/327 : which are undetectable to the naked eye, e.g. embedded codes
• CPC Class Codes: H04N 2201/3271 : Printing or stamping
• CPC Class Codes: H04N 2201/3274 : Storage or retrieval of prestored additional information
• CPC Class Codes: H04N 2201/328 : Processing of the additional information

Abstract

An embedded signal detection process determines a transformation of a media signal subsequent to the encoding of an embedded code signal into the media signal. The process performs a logarithmic sampling of the media signal to create a sampled signal in which scaling of the media signal is converted to translation in the sampled signal. It then computes the translation of the embedded code signal in the sampled signal to determine scaling of the media signal subsequent to the encoding of the embedded signal in the media signal.

Claims

1. A method of determining a transformation of a media signal having an embedded code signal, the method comprising:

performing a logarithmic sampling of the media signal to create a sampled signal in which scaling of the media signal is converted to translation in the sampled signal; and

computing translation of the embedded code signal in the sampled signal to determine scaling of the media signal subsequent to the encoding of the embedded signal in the media signal.

2. The method of claim 1 wherein the embedded code signal comprises a set of impulse functions in a transform domain.

3. The method of claim 2 wherein the impulse functions are have random or pseudo random phase.

4. The method of claim 1 wherein phase attributes of the embedded code signal is used to compute translation.

5. The method of claim 4 wherein the media signal comprises an audio signal.

6. The method of claim 4 wherein the embedded code signal is comprised of two or more components, and the phase attributes comprises pseudo random phases of the two or more components.

7. The method of claim 6 wherein the two or more components comprise impulse functions in a transform domain.

8. The method of claim 7 wherein the media signal is an audio signal.

9. The method of claim 1 wherein the media signal comprises an audio signal.

10. The method of claim 1 wherein the logarithmic sampling is performed on transform domain data of the media signal.

11. The method of claim 1 wherein the embedded code signal comprises a set of impulse functions, the media signal is a two dimensional signal and including:

performing a logarithmic sampling of each dimension of the media signal to create the sampled signal; and

computing translation of the embedded code signal in the sampled signal to determine scaling of the media signal in each of the dimensions.

12. The method of claim 11 wherein the impulse functions are in a transform domain and logarithmic sampling is performed on transform domain data of the media signal.

13. The method of claim 1 wherein the embedded code signal comprises a set of impulse functions, the media signal is a three dimensional signal and including:

performing a logarithmic sampling of each of the three dimensions of the media signal to create the sampled signal; and

computing translation of the embedded code signal in the sampled signal to determine scaling of the media signal in each of the dimensions.

14. The method of claim 13 wherein the set of impulse functions are in a transform domain and the logarithmic sampling is performed on transform domain data of the media signal.

15. The method of claim 13 wherein the media signal comprises a sequence of video frames and the three dimensions comprise vertical and horizontal spatial dimensions in each frame and a temporal dimension of the sequence of frames.

16. The method of claim 1 wherein the media signal is a two dimensional signal and including:

performing a logarithmic and polar sampling of the two dimensional signal to create the sampled signal in which both scaling and rotation of the two dimensional signal are converted to translation in the sampled signal; and

computing translation of the embedded code signal in the sampled signal to determine scaling and rotation of the media signal.

17. The method of claim 16 wherein the logarithmic or polar sampling is performed on transform domain data of the media signal.

18. The method of claim 1 wherein the media signal is a sequence of video frames and including:

performing a logarithmic and polar sampling of one or more frames and a logarithmic sampling of the temporal dimension of the sequence of frames to create sampled signals; and

computing translation of the embedded code signal in the sampled signals to determine scaling and rotation of one or more frames and temporal scaling of the frames relative to the media signal at an encoding time of the embedded code signal.

19. A computer readable medium on which is stored software for performing the method of claim 1.

20. A method of determining orientation of an embedded code signal in a media signal that has been transformed since encoding of the embedded code signal in the media signal, the method comprising:

performing a logarithmic sampling of the media signal to create a sampled signal in which scaling of the media signal is converted to translation in the sampled signal; and

computing translation of the embedded code signal in the sampled signal to determine scaling of the embedded code signal subsequent to the encoding of the embedded signal in the media signal.

21. The method of claim 20 wherein the embedded code signal comprises a set of impulse functions in a transform domain.

22. The method of claim 21 wherein the impulse functions have pseudo random phase.

23. The method of claim 20 wherein the media signal comprises an audio signal.

24. The method of claim 20 wherein the media signal is a two dimensional signal and including:

performing a logarithmic and polar sampling of the two dimensional signal to create the sampled signal; and

computing translation of the embedded code signal in the sampled signal to determine scaling and rotation of the embedded code signal.

25. A computer readable medium on which is stored software for performing the method of claim 20.

26. A system for determining a transformation of a media signal having an embedded code signal, the method comprising:

means for performing a logarithmic sampling of the media signal to create a sampled signal in which scaling of the media signal is converted to translation in the sampled signal; and

means for computing translation of the embedded code signal in the sampled signal to determine scaling of the media signal subsequent to the encoding of the embedded signal in the media signal.

27. The system of claim 26 wherein the media signal is an audio signal.

28. The system of claim 26 wherein the scaling of the media signal is used to determine orientation of the embedded code signal in the media signal.